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26 Cards in this Set
- Front
- Back
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FORCE
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*a push or pull that CAN cause a change in motion
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MAGNITUDE
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* strength or size
* length of vector = magnitude of force |
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VECTOR
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* arrow - represents a force
* head = direction of force * tail = magnitude of force |
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NEWTON
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* unit used to measure force
* = amount of force required to accelerate 100 g at a rate of 9.8 m/s/s (9.8 m/s/s = the rate of acceleration due to gravity) * 1-N = the force of gravity acting on a 100-g object * named for Sir Isaac Newton |
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SPRING SCALE
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* equipment used to measure force
* stretch of spring measures force exerted * used to measure weight (gravity) |
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BALANCED FORCES
EQUILIBRIUM |
* when net force = 0
* object will not change its motion * no acceleration takes place * forces cancel each other out |
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UNBALANCED FORCES
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* Net force > 0
* object changes its motion – speeds up, slows down and/or changes direction * object accelerates in the direction of greatest force |
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NET FORCE
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* sum of all forces acting on object
* positive number (no negatives) * vector or directional word indicates which way object will accelerate (i.e. 15N right or 15 N -->) |
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FREE BODY DIAGRAM
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* shows combination of all forces acting on an object
* uses a box and labeled vectors |
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NORMAL FORCE / SUPPORT FORCE
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* applied to object resting on a surface
* acts at right angle (perpendicular) to surface * contact force * abbrev. = norm |
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FRICTION
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* caused when 2 surfaces come together
* slows things down * acts in opposite direction of movement * contact force * many types: sliding/rolling/static/fluid * abbrev. = fric |
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STATIC FRICTION
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* found between 2 surfaces in contact but are NOT moving
* stronger than kinetic friction * decreases when object is in motion * contact force |
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KINETIC FRICTION
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* found between 2 surfaces in contact but ARE moving
* 3 types: sliding, rolling, fluid |
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SLIDING FRICTION
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* found when 2 surfaces skim across each other
* greater w/rougher surfaces * greater w/heavier objects |
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ROLLING FRICTION
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* found between 2 surfaces when one "wheels" or turns over the other
* is less than sliding friction * if force applied < static friction then rolling occurs * if force applied > static friction then spinning occurs (think car on wet road) |
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FLUID FRICTION
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* aka DRAG
* found between objects in contact w/ liquids or gases (aka fluids) * air resistance = when object's in air * faster movement > fluid friction |
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REDUCING FRICTION
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* 3 ways
* LUBRICATING - separating surfaces with slick substances * BALL BEARINGS - using wheels to allow objects to roll * STREAMLINING - using aerodynamic shapes so goes through fluid more easily |
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RELATIONSHIPS W/ FRICTION
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1) friction > when 1st started than when in motion
2) rougher surface = greater friction 3) heavier object = greater friction 4) direction of friction = opposite motion 5) rolling friction < sliding friction 6) faster the motion > fluid friction |
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CENTRIPETAL FORCE
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* describes another force that causes an object to move in circles (constantly changing direction)
* means "center seeking" * force points toward middle of circle * w/o it, object would move in straight line * abbrev. = cent |
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NEWTON'S FIRST LAW OF MOTION
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* objects have INERTIA (= lazy)
* they will do what they were doing unless an unbalanced force is applied * objects at rest stay at rest & objects in motion stay in motion in a straight line unless unbalanced force is applied |
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GRAVITY
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* force of attraction of all objects in universe for all other objects in universe
* a "together force" not just a "down" force * more mass = more gravitational pull * ALL objects exert gravitational pull toward ALL other objects * ALL objects are acted upon by Earth's gravitational pull the same (as long as air resistance is disregarded) - so ALL objects fall at the same rate * abbrev. = grav |
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TENSION/TENSILE FORCE
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* transmitted through material (such as: wire, string rope) when it is pulled
* stretching type force * abbrev. = tens |
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ELECTRICAL FORCE
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* attractive force between oppositely charged particles (i.e. protons and electrons)
* repelling force between like charged particles (i.e. two electrons) * abbrev. = elec |
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AIR RESISTANCE
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* type of friction acted upon objects traveling through air
* AKA drag * abbrev. = air |
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MAGNETIC FORCE
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* force of attraction or repulsion between two magnets
* abbrev. = mag |
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APPLIED FORCE
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* name of pushes or pulls "given to" (applied) another object that don't already have special names
* i.e. - when you push your brother * abbrev. = air |
